1. Field of the Invention
This invention relates to the operation of flush valves and, more particularly, to non-contact sensor operated mechanisms for operating flush valves.
2. Description of the Prior Art
The use of flush valves for controlling the flow of water to plumbing fixtures, particularly public facilities, is well-known. Such flush valves typically include a movable diaphragm which closes the water supply and is tripped by a handle operated trip mechanism. See, for example, U.S. Pat. Nos. 1,756,263; 1,858,470; 4,202,525 and 4,327,891. Push button arrangements for tripping diaphragm flush valves have also been developed. See, for example, U.S. Pat. Nos. 3,695,288 and 3,778,023. All of these arrangements provide controlled, on demand flushing of the plumbing fixture through controlling the flush valve trip mechanism.
It has long been recognized that human contact with the handle, push button or other device for tripping the flush valve is not particularly sanitary, especially in heavily used public restroom facilities. It has also been recognized that non-contact arrangements for tripping a flush valve are desirable. The most common non-contact method activating a flush valve is the use of a sensor operated system. See, for example U.S. Pat. Nos. 2,438,207; 2,603,794; 3,339,212; 3,434,164; 3,462,769; 3,670,167; 3,863,196; 4,309,781; 4,624,017; 4,667,350; 4,707,867; 4,742,583; 4,793,588 and 4,805,247. These systems provide for automatic tripping of the flush valve by first detecting when a person is present at the plumbing fixture, then detecting when the person leaves the fixture and then triggering the flush mechanism for the fixture. All these systems provide for non-contact and sanitary flushing of the plumbing fixture; it does so at the expense of the user's direct control of the flush mechanism, which is present in the handle and the push button operated systems. To overcome this deficiency, several sensor operated flush valves have incorporated a push button override. This override enables the user or maintenance worker to flush the flushing device on demand. However, the mechanical override is unsanitary and subject to vandalism--like the above-identified on demand systems.
Furthermore, the above-described sensor operated flush valves without the mechanical override tend to make maintenance procedures on the urinal or toilet difficult. Specifically, after a maintenance worker applies cleaning solution to the toilet bowl or the urinal bowl, he or she must move away from the bowl to activate the flush valve to clear the cleaning solution from the bowls. This is a cumbersome procedure and in many cases ignored. Also, if a maintenance person must do work to the bowl, for example check for leaks, the flush valve needs to be disabled. This requires either shutting off the electrical power to the sensor or the flush valve and typically involves removing a face plate from the sensor to obtain access to a power control box. This procedure is likewise cumbersome and time-consuming.
Accordingly, it is an object of our present invention to provide a non-contact sensor for operating a flush valve in which a maintenance worker can easily disable or override the sensor while a user cannot easily disable or override the sensor.